Sandwich-walled cylindrical shells with lightweight metallic lattice truss cores and carbon fiber-reinforced composite face sheets

We manufactured sandwich-walled cylindrical shells with aluminum pyramidal truss core of constant curvature employing an interlocking fabrication technique for the metallic core. The skins were made of carbon-fiber reinforced composites and co-cured with the metallic truss core. Thereafter, we carried out axial compression tests on some representative samples to investigate the failure modes of these structures and compared with an analytical failure map developed to account for Euler buckling, shell buckling, local buckling between reinforcements and face-crushing. The experimental data closely matched the analytically predicted behavior of the cylinders. In particular, we found that local buckling and face crushing modes can exist together and are the most important modes of failure of the fabricated structure.